This invention relates to electrochromic displays and more particularly to electrochromic displays adapted for multiplexing of electrode-segments and counter-electrodes.
In recent years a great deal of interest has been shown in the provision of electrochromic displays having, for example, a digital readout such as in U.S. Pat. No. 3,839,857 issued Oct. 8, 1974 to Donald Joseph Berets, et al.
Typically, the prior art electrochromic displays consist of a cell having indicia each formed by a plurality of electrode-segments which are coated with an electrochromic material, said electrode-segments each being separately connected to/from the display for separate energization thereof, a single common electrode associated with a plurality of indicia, and a single electrolyte layer associated with said plurality of indicia and the common electrode. However, these prior art electrochromic displays had many drawbacks such as requiring a large number of electrical connections to the display and the inability to multiplex because of cross-talk, i.e., leakage current, which may cause unwanted activation of other electrode-segments.
As is known to those skilled in the art of producing electrodes and leads, each input point to electrical apparatus, such as an electrochromic display, is a potential trouble point and thus the elimination of input points is an elimination of potential trouble points, and accordingly, it is most desirable to provide electrical apparatus, such as an electrochromic display, with a minimum of electrical input points.
Accordingly, it is an object of the present invention to provide an electrochromic display adapted for multiplexing of electrode-segments with separate counter-electrodes and reducing the lead or electrical connections to/from and on the electrochromic display.
It is a further object of the invention to provide a new and improved electrochromic display device having a plurality of electrically isolated counter-electrodes.
An electrochromic display comprising in sandwich layered form a first transparent substrate with a plurality of indicia formed thereon, said indicia each consisting of a plurality of selectively energizable transparent electrodes with each corresponding transparent electrode in each indicia being interconnected on the first transparent substrate to form groups of commonly energizable segments with each group having a single or common electrical connection to/from the display, a layer of electrochromic material on each of the transparent electrodes, a second substrate with a plurality of separate counter-electrodes each being associated with an indicia and electrically isolated from all other counter-electrodes, and a separate electrolyte layer between each counter-electrode and its associated digit.